Ship project history:
First capital ships
built in Japan and first-ever cruisers armed with 12``
guns in twin turrets. They
were ordered in June, 1904 as replacement of lost
battleships Hatsuse and Yashima and laid down even before end of the Russian-Japanese war. Building of the ships has been interfaced to industrial problems because of what
lead-ship Tsukuba possessed numerous defects.
Commission of Ikoma was delayed by shortage of
main artillery: ship has gone out on sea trails in November, 1907, but completely has been armed and
completed only by February,
1911. On measuring mileTsukubahas shown 20.5ktsat 20736hp,
Ikoma made 21.9ktsat 22670hp.

Ship protection:
Krupp steel. Main belt, extended to 1.2m under wl, was 178mm between
barbettes and 102mm at ship ends. The upper belt between barbettes was 127mm,
casemates had also 127mm protection. Barbettes and turrets had 178mm armour.
There were main CT with 203mm sides and aft CT with 152mm sides. Protected deck
was 51mm amidships and 76mm at ship ends.

Naval service:Tsukuba was lost at Yokosuka as a result of
magazines explosion; crew losses have made 305 persons the killed. Ikoma since 1919 served as
gunnery training ship. Soon after Washington conference,
in 1922,she was disarmed and sold for BU 13/11/1924.